Thanks Jim.  I ended up with only 54 entries in the distribution list and didn't experience any issues other than the expected handful of delivery failures.

I am in the process of creating my first distribution list of any significant size in Pegasus Mail.  I anticipate around 70 entries.  MercuryE will be handling the sending.  I won't be surprised to receive a number of invalid address errors due to the list source being a couple of years old.  

I recall discussions in the past about large dlists and problems with being flagged as a spammer so am curious whether 70 records is of concern and if so, how do I mitigate any potential problems.

TIA!

In mercury there is something called Fanout when you create a distribution list but there is no comparable option in Pegasus.   I'm not 100% sure but I think Pegasus creates a separate message for each recipient so it shouldn't be a problem unless your isp specifically forbids sending to too many recipients.  I just did a test distribution to 2 users on my own server and when mercury sent the message it made 2 different connections to deliver.  When you bcc a bunch of people mercury will only make 1 connection to each server and deliver as many messages as it can in one connection which sometimes causes a problem.

Hope that makes sense....